Threading issue on AS 6

[asiandub]

I'm currently facing a problem with my web application which I'd like to discuss here:

The application (JEE 6 / JSF) is deployed on a single AS and performs pretty well overall (knock on wood ;-))

The problem however starts when certain user actions are executed (excel exports of huge report) - the report generation itself takes about 5-10 minutes, which is quite okay for us. Definitely not okay is the fact that the system load goes up to 100% an the application becomes totally inresponsive while the export runs. :-(

I'm looking for a way to priorize the heavy load tasks and to guarantee that the system stays usable while the export runs.

Simply getting a handle to the current thread and setting its priority to Thread.MIN_PRIORITY feels a bit short sighted, because I assume that after a while all threads in JBoss' thread pool are downgraded. But I can be wrong - so I'd be glad if someone could push me in the right direction...

Cheers,

Jan

[asiandub]

update: what we implemented as a quick workaround:

- set priority of current thread to minimum

- perform heavy work

- set priority of current thread back to normal (in a finally block)

works pretty much as expected - but feels like a quick and dirty hack...

any better suggestions?

cheers,

Jan

[asiandub]

it seems like not too many people are having issues with threads ;-)

Anyhow, should someone be confronted with a similiar situation, here's my conclusion:

- the described way works pretty good and stable, even under production load (internal application, max 10 parallel users)

- re-adjusting the priority after "heavy work" is finished is certainly good style, but probably not required, as the default keep-alive time of a thread (see default configuration below) is one minute. So my doubt that all threads will be downgraded after a while is false - no thread will be kept alive and idle longer than one minute...

<mbean code="org.jboss.util.threadpool.BasicThreadPool"

name="jboss.system:service=ThreadPool">

<attribute name="Name">JBoss System Threads</attribute>

<attribute name="ThreadGroupName">System Threads</attribute>

<attribute name="KeepAliveTime">60000</attribute>

<attribute name="MaximumPoolSize">10</attribute>

<attribute name="MaximumQueueSize">1000</attribute>

<attribute name="BlockingMode">run</attribute>

</mbean>

- in case that finer adjustments are required: the jmx console allows to dump all current threads, this should give a good overview of what's going on at the moment.

Hope it helps others :-)

cheers,

Jan